D9R and 463 pull scraper

[ihbuilder]

Originally Posted by dirtpusher9

Standard in size I guess is what I meant to say, they are Buna, made for hydraulic applications.

Henry, you would save a lot of time just getting the tubing insted of boring them. I would use 260/330 brass tubing and just a polished steel precision ground rod. I think I went with the 260 brass on my cylinder (been laying there a couple years, can't remember).

Joe's right Clyde , trust me I've been there and lost some hair . I got some seemless ss tube and rod . I was going to tread both ends of the tube and make brass ends but I like joe's glad end set up

IHSteve

[tracksntreadslou]

Another option is to check the local auto wreckers for hatchback cyclinders...Rod diamater is fairly close to scale size and if your careful you may be able to salvage seals ..might be worth a try

[JAMMER]

Henry don't get the inside of the cylinder to smooth you have to have some roughness so the oil will hold on, a polished surface is not good I am using brake cylinder hones on my cylinders and some I got from a place in Florida that they use on automatic transmissions to clean up bores. Ed

[sparkycuda]

Joe, awesome job, as usual. Do you have a reference for sizing the o-ring grooves? O-rings are easy to find, but I'm not sure how much clearance or squish to allow for proper sealing without excessive sliding resistance. Did you solder the large end on to the barrel or turn it from one piece of thick-wall tube? Thanks!

Ken

[pugs]

Originally Posted by sparkycuda

Do you have a reference for sizing the o-ring grooves? O-rings are easy to find, but I'm not sure how much clearance or squish to allow for proper sealing without excessive sliding resistance.

Machinerys handbook has all that info in, strongly suggest anyone that tinkers with machining get a copy, lots and lots of good info.

O-ring groove sizes are in my 25th edition on page 2400.

[sparkycuda]

Thanks Joe and everyone for the response and advice about the orings. My Komatsu dozer is a very slow build. Been traveling a lot for work - last time I even took my mini-lathe and turned out four bottom rollers during the evenings at the hotel. I finally figured out the drivetrain and got gears, bearings and motors. Have modified cordless drill planetaries for the final drive and sourced pinion and bullgears along with bearings. Got a mini-mill about a month ago and have practiced using it - much more accurate and easy to use than the Dremel-in-a-drill-stand I "machined" the pivot shaft covers with. I will be building the tracks completely, which will take time, but have found only one product that is close to correct pitch (20.4 mm) for my dozer, but would cost about $500 just for the links and pads - too much for my wallet. Have taken pictures - just reluctant to post yet, since it will be a while before it looks like anything. I am always amazed how quickly some of you build things - to me it's astonishing fast! Machining is a skill I'm aquiring slowly - have to double check everything I do, which slows completion times. But I'm getting better at it. Seeing the work that people on this forum do, keeps me motivated.

Sorry for the lengthy posting...

Ken